Field of the Invention
This invention relates to systems for purifying and drying process gases and more particularly, to a blade and skirt assembly for a directional gas cleaning and drying system which is typically installed in a pipeline for removing solid and liquid impurities from a process gas, natural gas or steam in the pipeline. The directional gas cleaning and drying system is typically characterized by a vertical, cylindrical gas vessel having an annular interior adsorption surface. The blade and skirt assembly of this invention includes multiple, angled vortex blades extending horizontally outwardly from a central cone-shaped blade hub, with the edges of the vortex blades typically welded to the adsorption surface. A cone-shaped dispersal skirt of the blade and skirt assembly is typically welded to the blade hub, and the intake end of a gas outlet arm faces the flared bottom rim of the dispersal skirt in the gas vessel interior. In a preferred embodiment, multiple gas flow vanes are provided on the sloped dispersal surface of the dispersal skirt. After the gas flows typically by vacuum-induced service from. the pipeline into the gas vessel, the gas flows through the stationary vortex blades, which direct the gas in a descending spiral path. The circulating gas strikes the sloped dispersal surface and gas flow vanes of the dispersal skirt, which remove some of the solid and liquid impurities from the gas by adsorption and deflect the gas against the adsorption surface. The remaining solid and liquid impurities in the swirling gas are forced against the annular adsorption surface by centrifugal force and initially adhere to the surface by adsorption. The swirling, purified gas then travels in an inner spiral path around the intake portion of the gas outlet arm and ultimately enters the arm, through which the purified gas exits the gas vessel and typically re-enters the pipeline. The solid and liquid impurities, adsorbed on the dispersal skirt and adsorption surface, gravity-drain into a sump provided at the bottom of the gas vessel and which is periodically emptied.
When natural gas is produced from a gas well or recovered with hydrocarbons from an oil well, moisture and solid impurities such as sand particles, brine, crude oil and distillates are typically present in small quantities in the gas. The impurities, if unremoved from the gas, tend to lower the combustibility of the gas and thus render the gas less economical to burn for power generation or other industrial purposes. Some of the impurities in the gas emit toxins upon combustion, thus posing environmental risks if unremoved from the gas. Purification of natural gas thus both enhances the combustion characteristics of the gas for power production or other purposes and contributes to a cleaner environment. Additionally, the impurities should be removed from the natural gas stream before distribution to a remote source in a gas pipeline since the solid contaminants in the gas have a tendency to plug or corrode some of the distribution piping in the pipeline over time and thus, hinder gas flow through the piping.
A recent patent of interest which discloses an apparatus for removing contaminants from a gas stream is U.S. Pat. No. 5,735,937, entitled xe2x80x9cMethod for Removing Contaminants from a Gas Streamxe2x80x9d, dated Apr. 7, 1998, to Dingfelder. According to the Dingfelder separation method, a gas contaminant separator includes a pressure tube, and a concentric down pipe in the pressure tube and connected to a gas inlet conduit defines an annular space between the pressure tube and the down pipe. A helical rib extends from the surface of the down pipe and into the annular space, and multiple magnets are mounted on the down pipe between the helical rib and a perforated plate. The rotating motion of the gas imparted by the helical rib in the annular space causes the heavier contaminated particles to separate from the gas and collect along the surface of the down pipe. Further, the combined actions of the magnetic field, created by the magnets, and the perforated plate enhance coalescence and cross-linking of long-chain polar molecules in the gas such that the heavier, cross-linked contaminant molecules fall out of the gas stream.
Another patent of interest which involves purification of gas streams is U.S. Pat. No. 5,788,745, dated Aug. 4, 1998, to Hahn and entitled, xe2x80x9cProcess and Apparatus for Vapor Recoveryxe2x80x9d. The Hahn process includes contacting a gas stream to be purified with an absorbent to remove water and hydrocarbon impurities from the gas stream. After their removal from the absorbent, the impurities are discarded.
U.S. Pat. No. 6,059,859, dated May 9, 2000, to Alvarez, Jr., et al, details a xe2x80x9cMethod, Composition and Apparatus for Water Removal from Non-Corrosive Gas Streamsxe2x80x9d, in which a gas to be purified is passed through a dehydrating agent provided in a cynical container that is installed in a gas supply line for the gas. The dehydrating agent is a pelleted or granulated oxide or salt of an electropositive metal.
Still another gas purifying system known in the art for separating solid and liquid impurities from a process gas is the directional gas cleaning and drying system, characterized by a cylindrical vessel having an interior adsorption surface, with multiple, angled blades extending from a central hub and the edges of the blades typically welded to the annular adsorption surface. After the gas enters the vessel under positive or negative pressure from a pipeline, the gas flows through the blades, which cause the gas to flow in a descending spiral path toward the adsorption surface, and many of the solid and liquid impurities initially present in the gas are forced against the adsorption surface by centrifugal force and adsorbed onto the surface. The swirling, partially purified gas enters a gas exit pipe which conveys the gas from the vessel, while the solid and liquid impurities, adsorbed on the adsorption surface, gravity-flow down the adsorption surface into a sump which is periodically emptied. While the stationary blades are effective fi)r dispersing much of the solid and liquid impurities from the gas and onto the adsorption surface, the spiral path of the gas imparted by the blades is typically insufficiently narrow to facilitate contact of all of the swirling gas with the adsorption surface. Consequently, some of the solid and liquid impurities wherein in the gas upon exit from the vessel. Therefore, a new and improved mechanism is needed for enhancing separation of the solid and liquid impurities from the gas in the vessel.
Accordingly, an object of the. present invention is to provide a blade and skirt assembly for enhancing removal of impurities from a gas in a directional gas cleaning and drying system.
Another object of the invention is to provide a blade and skirt assembly for a directional gas cleaning and drying system which is typically installed in a gas pipeline for purifying and drying a process gas in the pipeline.
Still another object of this invention is to provide a blade and skirt assembly for removing solid and liquid impurities from a gas or steam, typically as the gas or steam flows through a pipeline.
Yet another object of the invention is to provide a new and improved blade and skirt assembly for a directional gas cleaning and drying system having a gas vessel and an interior adsorption surface provided in the gas vessel, which blade and skirt assembly is characterized by a central blade hub having multiple, angular vortex blades extending outwardly from the blade hub and a cone-shaped dispersal skirt disposed between the vortex blades and the intake end of a gas outlet arm which distributes the gas from the gas vessel typically to a gas outlet conduit of a gas pipeline, with multiple gas flow vanes provided on the sloped dispersal surface of the dispersal skirt, such that the angular vortex blades initially direct the flowing gas in a spiral path; the gas flow vanes and the sloped dispersal surface of the dispersal skirt deflect the swirling gas outwardly against the adsorption surface, wherein some of the solid and liquid impurities in the gas are adsorbed onto the gas flow vanes and dispersal surface of the dispersal skirt; the solid and liquid impurities in the partially-purified gas, swirling along the annular adsorption surface in a spiral path, are forced against the adsorption surface by centrifugal force and adsorbed onto the surface to further purify the gas; and the substantially purified and dried gas initially swirls in an inner spiral path around the intake portion of the gas outlet arm and then enters; the gas outlet arm, through which the gas exits the gas vessel and typically re-enters the pipeline.
A still further object of the invention is to provide a blade and skirt assembly for a directional gas cleaning and drying system, which blade and skirt assembly is characterized by multiple, angular vortex blades extending outwardly from a typically cone-shaped blade hub mounted in a gas vessel having an interior adsorption surface; and a cone-shaped dispersal skirt typically welded or otherwise attached to the blade hub, wherein gas enters. the gas vessel from a gas pipeline, the vortex blades direct the gas in a spiral path against the dispersal skirt and the dispersal skirt widens the spiral path of the swirling gas against the adsorption surface to facilitate adsorption of solid and liquid impurities by centrifugal force from the gas onto the adsorption surface.
Another object of the invention is to provide a new and improved directional gas cleaning drying system characterized by a gas vessel having an interior adsorption surface and adapted for receiving a process gas such as natural gas typically from a gas pipeline; and a blade and skirt assembly provided in the gas vessel, which blade and skirt assembly includes a blade hub; multiple, angular vortex blades extending outwardly from the blade hub; and a cone-shaped dispersal skirt disposed between the vortex blades and the intake end of a gas outlet arm with the sloped surface of the dispersal skirt fitted with multiple, spaced-apart gas flow vanes and facing the vortex blades, such that pressurized gas enters the gas vessel and flows through the blade and skirt assembly, the stationary vortex blades of which impart a spiral flow to the gas; the sloped dispersal surface of the dispersal skirt, in combination with the gas flow vanes, deflects the swirling gas outwardly in a widening spiral path against the annular adsorption surface and solid and liquid impurities in the gas are adsorbed onto the gas flow vanes and dispersal surface of the dispersal surface, as well as onto the adsorption surface by centrifugal force; and the purified gas then swirls in an inner spiral path around the gas outlet arm and finally, leaves the gas vessel through the gas outlet arm and re-enters the pipeline.
These and other objects of the invention are provided in a new and improved blade and skirt assembly for a directional gas cleaning and drying system which is typically installed in a gas pipeline for removing solid and liquid impurities from steam or a process gas such as natural gas in the pipeline. The blade and skirt assembly is mounted in a directional gas cleaning and drying system typically characterized by a vertical, cylindrical gas vessel having an annular interior adsorption is surface. The blade and skirt assembly includes multiple, angular vortex blades extending outwardly from a central cone-shaped blade hub provided in the gas vessels with the edges of the vortex blades typically welded to the annular adsorption surface. A cone-shaped dispersal skirt of the blade and skirt assembly is typically welded to the blade hub beneath the vortex blades, and multiple gas flow vanes are typically provided on the sloped dispersal surface of the dispersal skirt. The intake end of a gas outlet arm, typically connected to the pipeline, is disposed in facing relationship to the flared bottom rim of the dispersal skirt. After flowing into the gas vessel from the gas pipeline, the gas flows downwardly through the blade assembly, the stationary vortex blades of which direct the gas in an initially descending, spiral path. Some of the solid and liquid impurities in the deflected gas are adsorbed onto the gas flow vanes are sloped dispersal surface of the dispersal skirt. The dispersal skirt and gas flow vanes deflect the swirling, partially-purified gas outwardly in a widening spiral path against the annular adsorption surface, where the gas swirls along the annular adsorption surface in a slowly-descending spiral path and solid and liquid impurities in the gas initially adhere to the adsorption surface by centrifugal force and drain into a sump which is periodically emptied. The substantially purified and dried gas swirls upwardly in an inner spiral path around the intake portion of the gas outlet arm and enters the arm, through which the purified gas exits the gas vessel and typically re-enters the pipeline. In another embodiment of the blade and skirt assembly, the gas flow vanes are omitted from the sloped dispersal surface of the dispersal skirt.